This invention is directed to a threaded plug and tamper evident, hand applied seal for shipping drums.
In today""s global political climate the security of drummed products is coming under ever closer scrutiny. This, coupled with the need for normal tamper vigilance, is driving a trend toward the increased use of effective tamper indicating seals on all types of shipping containers. It has long been the practice to apply overseals of one kind or another with special hand and power tools which were able to crimp a metal portion of the overseal tightly around an upstanding opening neck designed to receive the seal. These type overseals are rather costly as are tools for their application. Moreover, the application step itself is quite labor intensive and relatively inefficient. Consequently a number of hand applied overseals have come forth which to a certain degree obviate the above mentioned applications tools. These overseals are for the most part easily snapped onto the container opening neck and usually almost as easily snapped off. While these plastic snap-on caps serve to dress up a container such as a 55 gallon drum, giving the closure area a finished appearance and some added degree of cleanliness, there is still much to be desired in terms of drum security. To be effective such drum closure overseals need to meet a number of rather demanding criteria. Obviously the hand application has to be simple and relatively effortless to satisfy normal filling line speeds. Once the drum is shipped, of paramount importance is the ability of the overseal to guard against unauthorized access to the drum contents. This means that the overseal cannot be physically removed without destroying same or making such unauthorized access clearly noticeable and such that the overseal cannot be reapplied in unaltered form to the drum closure. In this regard, those all plastic manually applied overseals currently in general use for both steel and plastic drums are, for the most part, easily pried off in an undetect manner particularly when in a warmed state. In other words xe2x80x9ceasy on easy offxe2x80x9d.
Also of importance is the ability of the overseal to resist inadvertent damage during handling and shipment. Commonly employed tamper detection devices such as frangible locking rings, shrink bands and the like found on consumer packages are not at all suited for use on 55 gallon drums. One can easily see that any inadvertent or accidental damage to the tamper resistant overseal immediately raises the question, has the drum security been breached or compromised in some way? Or is this simply damage to be expected resulting from normal handling? This aspect dictates any tamper detecting feature be sufficiently robust to remove any question of doubt as to whether unauthorized entry has in fact occurred.
A performance criteria also of major importance is the ease with which the overseal can be removed from the underlying drum closure in an authorized manner such that subsequent replacement of the overseal is not possible. Normally this requires destruction of the overseal in some fashion to prevent reuse. In this regard the use of sharp cutting or puncturing implements is undesirable due to the likelihood injury or of accidental damage to the underlying closure. Thus, in addition to the overseal""s robust construction, hand removeability is yet another advantageous attribute.
The above described prior art deficiencies are effectively overcome by the advent of the instant invention disclosing a new and improved closure plug and tamper resistant overseal. The plug is formed as a shallow cup having a threaded cylindrical sidewall and a circumferentially enlarged head. Wrench engaging lugs are formed within said sidewall. Interlocking structure is provided on the plug for securement of a hand applied, tamper evident overseal. The overseal is an integrally molded plastic cap which can be manually snapped onto the plug so as to cover the same and the surrounding container neck structure. This construction immediately eliminates the need for any kind of crimping or applying tools and the relative inconvenience attendant thereto. Moreover, going well beyond the prior art all plastic seal arrangements, the invention overseal is so constructed that removal without destroying the seal is virtually impossible. This is accomplished by integrally molding a segmented collet depending axially from a central portion of the plastic cap. Each segment of the collet has a radially enlarged foot and can be spring biased radially. To apply the overseal to an upstanding container neck with the plug screwed in place, the plastic cap is pressed on top of the plug by hand causing the feet on the semented collet to snap into the interlocking structure on the plug. The resulting interengagement is such that unauthorized removal of the overseal is prevented. Unlike other prior art arrangements the relative inaccessibility of the segmented locking collet renders any kind of pry off tool quite useless.
When it comes to removal in an authorized manner the plastic cap is provided with a diametrically extending tear strip defined by a pair of score lines and diametrically opposed gripping ears. Once the tear strip is torn the engagement by the segmented collet is released and the overseal easily removed. However, unlike prior art all plastic seals, the invention overseal is quite obviously destroyed and rendered completely unusable for resealing.
It is accordingly a principal object of the invention to provide a new and improved drum plug and overseal combination.
Another object is to provide an improved threaded drum plug with seal interlocking features.
Still another object is to provide a new and improved tamper evident overseal for drum closures.